Thesis (MSc (Medical Virology )--University of Stellenbosch, 2004. / 150 leaves printed on single pages, preliminary pages i-vii and numberd pages 1-143. Includes bibliography and figures digitized at 300 dpi grayscale and 300 dpi 24-bit Color to pdf format (OCR), using a Hp Scanjet 8250 Scanner and digitized at 600 dpi grayscale to pdf format (OCR), using a Bizhub 250 Konica Minolta Scanner. / ENGLISH ABSTRACT: The first episode of HIV-1 in South Africa was documented in 1982. Homosexual transmission of the virus was the predominate mode of transmission in an epidemic of mainly HIV-1 subtype Band D infections. To date, no full-length sequences of Subtype D strains from South Africa has been reported. Here we describe the characterization and some of the unique features of the Tygerberg HIV-1 subtype D strains. A near full-length 9 kb fragment was obtained through a one step PCR using high molecular weight DNA. Cloning was done successfully with the pCR-XLTapa cloning kit. Large quantities of plasmid DNA was grown and sequenced on both strands of the DNA. ORF determination and subtyping was followed by standard phylogenetic methods to construct evolutionary phylogenetic trees. Subtyping and similarity plots revealed that the sequences from Tygerberg are pure subtype D. All the Tygerberg strains had intact genes with no premature stop codons. At the tip of the V3 loop, the Tygerberg strains have the GOGO motif. R214 has a more variable vpu gene than the rest of the Tygerberg strains, but is still subtype D in this region. No premature stop codons have been observed in the tat gene and the glycosilation of the strains are less than the subtype D consensus. We are the first to report full-length sequences of HIV-1 subtype D strains from South Africa. The sequences represent non-mosaic genomes of subtype D. Our results confirm that the subtype D sequences from the beginning of the HIV-1 epidemic differ from the Subtype D sequences from recent isolates. / AFRIKAANSE OPSOMMING: Die eerste episode van HIV-1 infeksie in Suid Afrika is in 1982 gedokumenteer. Die epidemie het hoofsaaklik uit subtipe B en D bestaan en was deur homoseksuele kontak oorgedra. Geen vollengte subtipe D DNS volgordes van Suid-Afrika is tans beskryf nie. Hier beskryf ons die karakterisering van vollengte subtipe D stamme asook sommige van die unieke eienskappe van die virusse. Die vollengte 9 kb genoom volgorde was verkry deur 'n eenstap PKR reaksie met hoë molekulêre gewig DNS uit te voer. Die 9 kb fragment was suksesvol gekloneer met behulp van die peR-Xl-TOPO klonerings toetsstel. Groot hoeveelhede plasmied DNS was opgegroei en die nukleotied volgorde bepaal op beide stringe van die genoom. Die stamme was gesubtipeer en filogenetiese analise was uitgevoer met standaard metodes. Die volledige DNS volgordes was bepaal en subtipering het daarop gedui dat die stamme van Tygerberg suiwer subtipe D is. Geen premature stop kodons is in die nukleotied volgordes van die Tygerberg stamme gevind nie. By die draai van die varieerbare deel (V3) het al die Tygerberg stamme die GQGQ motief gehad. R214 het 'n meer varieerbare vpu geen, maar behoort steeds tot die subtipe D groep in die gedeelte. Daar was geen premature stop kodons in die tat geen gevind nie en die glikosilasie van die stamme is minder as die van die konsensus subtipe D stam. Ons is die eerste groep om vollengte subtipe D stamme van Suid-Afrika te karakteriseer. Die DNS volgordes verteenwoordig suiwer subtipe D genome. Ons resultate bevestig die van ander dat die nukleotied volgordes van die ouer subtipe D stamme verskil van die nuwer stamme.

Thesis (MScAgric)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: Historically root diseases have been a production-limiting problem for the strawberry industry worldwide. In the Western Cape Province of South Africa the most serious root disease is black root rot, which causes losses of up to 30%, annually. The aims of this study were to investigate aspects of the etiology and epidemiology of this disease in the Western Cape, and to provide information that can be incorporated in an integrated disease management strategy. In Chapter I a summary of published information on this disease is presented. Disease symptoms include severe stunting of plants, which have black, rotted, reduced root systems. Even though this disease is of great economic importance, the etiology remains unresolved. However, soilborne fungal root pathogens, particularly Pythium and Rhizoctonia spp. have been implicated as major role players. Control of this disease, as well as the other root diseases affecting strawberries, has relied on soil fumigation with broad spectrum chemical fumigants, in particular methyl bromide. However, due to the ozone depleting action of methyl bromide it was decided at the signing of the Montreal Protocol to remove this chemical from the market. This action has caused great demand for alternative measures to control root diseases on many crops including strawberries. Development of integrated disease management strategies is dependent upon a more complete understanding of the etiology, biology and ecology of the disease complex. In Chapter 2 fungal pathogens associated with diseased plants were isolated and Koch's postulates were carried out. The most frequently isolated fungal pathogens were Pythium irregulare, Rhizoctonia spp. and Cylindrocarpon destructans. Two morphotypes of Rhizoctonia were isolated viz. a brown and a white type. Pythium irregulare was isolated more frequently in July than in September, and was not isolated at all in November. Rhizoctonia spp. were present at all sampling dates but were more frequently isolated in November than at the other times. All the fungi that were tested were pathogenic and caused root lesions. Cylindrocarpon destructans and Coniella fragariae did not have a stunting effect on the plants. These results confirm a major role for Pythium and Rhizoctonia in the black root rot complex and suggest that there is a complimentary seasonal variation in occurrence between these two pathogens. The Rhizoctonia species and anastomosis groups of isolates obtained from diseased strawberries in the Western Cape Province were determined, and their pathogenicity and relative virulence assessed. Both binucleate and multinucleate types were recovered from diseased roots and identified as R. fragariae and R. so/ani, respectively. All isolates of R. solani were members of anastomosis group (AG) 6, whereas three AG types were identified among isolates of R. fragariae, viz. AG-A, AG-G and AG-I at a relative occurrence of 69%, 25%, 6% respectively. All Rhizoctonia isolates were pathogenic to strawberry, but R. solani (AG 6) was the most virulent causing severe stunting of plants. This is the first species confirmation and AG type identification of Rhizoctonia taxa causing root rot of strawberries in South Africa. An assessment of the presence and quantity of black root rot pathogens associated with soils prior to fumigation and post fumigation with methyl bromide, was made in Chapter 4. Isolations were also made from nursery plants to determine whether any black root rot pathogens were in the plants before transplanting. Results demonstrated that after fumigation the soil was free of all pathogenic fungi associated with the disease. However, the main pathogens involved in black root rot, viz. Rhizoctonia fragariae, R. solani and Pythium spp. were isolated from nursery plants. The fact that the plants are already infected with these pathogens renders the prospects for control of this disease difficult. Further studies are urgently required to develop production practices that can be included in disease management programmes. In vitro studies were carried out to determine the ECso values of different fungicides for isolates of Pythium irregulare, Rhizoctonia fragariae AG-A, AG-G and AG-I and R. solani AG 6. Benomyl, fludioxonil and tolc1ofos-methyl were used in these tests. Field trials were also conducted using these fungicides. In Chapter 5 it is shown that in general application of fungicides improved the yield and did not affect the survival rate of strawberry plants. Fludioxonil showed potential for short-term use. Applications of fungicides that targeted specific fungal genera were not sufficient to control the disease. Seasonal fluctuation of Pythium and Rhizoctonia spp. became apparent with the occurrence of Pythium being relatively high early in the season but low late in the season. Conversely, the occurrence of Rhizoctonia was low at the beginning of the season but high late in the season. In the short-term there is potential for fungicide applications as part of an integrated disease management strategy, but the economic feasibility of this practice needs to be assessed. In this study the major pathogens causing black root rot were identified in the Western Cape Province of South Africa, and important information regarding the epidemiology of the disease was reported. These results can be incorporated in an integrated management strategy to reduce losses of strawberry production, attJibutable to black root rot. / AFRIKAANSE OPSOMMING: Wortelsiektes is wêreldwyd 'n produksie-beperkende probleem vir die aarbeibedryf. . Swartwortelvrot, wat jaarliks verliese van tot 30% veroorsaak, is die belangrikste wortelsiekte in die Wes-Kaap Provinsie van Suid-Afrika. Die doelwitte van hierdie studie was om aspekte van die etiologie en epidemiologie van die siekte in die Wes- Kaap te ondersoek en inligting wat in geïntegreerde siektebestuurstrategië ingesluit kan word, te voorsien. In Hoofstuk 1 word 'n opsomming van gepubliseerde inligting aangaande die siekte uiteengesit. Siektesimptome sluit ernstige verdwerging van plante met swart verotte en verkleinde wortelstelsels in. Alhoewel die siekte van groot ekonomiese belang is, is die etiologie grootliks onbekend. Grondgedraagde wortelpatogene swamme, spesifiek Pythium en Rhizoctonia spp., is egter as belangrike rolspelers geïdentifiseer. Tot dusver het die beheer van hierdie siekte sowel as ander wortelsiektes van aarbeie berus op grondberoking met breë spektrum chemiese berokingsmiddels, spesifiek metielbromied. As gevolg van die osoonafbrekende aksie van metielbromied is daar egter tydens die ondertekening van die Montreal Protocol besluit om dié middel van die mark te verwyder. Hierdie besluit het 'n groot aanvraag na alternatiewe beheermaatreëls vir wortelsiektes van verskeie gewasse, insluitende aarbeie, veroorsaak. Die ontwikkeling van geïntegreerd siektebestuurstrategieë is egter afhanklik van 'n meer volledige begrip van die etiologie, biologie en ekologie van die siektekompleks. In Hoofstuk 2 is die patogene swamme wat met die siekte geassosieer word, geïsoleer, en is Koch se postulate uitgevoer. Die mees algemeen geïsoleerde patogene swamme was Pythium irregulare, Rhizoctonia spp. en Cylindrocarpon destructans. Twee morfotipes van Rhizoctonia is geïsoleer, nl. 'n bruin tipe en 'n wit tipe. Pythium irregulare is meer dikwels in Julie as in September geïsoleer, maar glad nie in November nie. Rhizoetonia het tydens alle monstertye voorgekom, maar is meer dikwels in November geïsoleer. Al die swamme wat getoets is, was patogenies en het letsels op die wortels veroorsaak. Cylindroearpon des true tans en Coniella fragariae het nie'n verdwergingseffek op plante gehad nie. Hierdie resultate bevestig die dominante rol van Pythium en Rhizoctonia in die swartwortelvrot kompleks en dui op 'n komplementêre seisoenale variasie in die voorkoms van hierdie twee patogene. Die Rhizoctonia spesies en anastomose groepe (AG) van die isolate geisoleer vanaf siek aarbeiplante in die Wes-Kaap Provinsie is bepaal, en die patogenisiteit en relatiewe virulensie is beraam. Sowel tweekernige as multikernige tipes is vanaf siek wortels geïsoleer en respektiewelik as R. fragariae en R. so/ani geïdentifiseer. Alle isolate van R. so/ani was lede van anastomose groep 6, terwyl drie AG tipes, nl. AGA, AG-G en AG-I onder die R. fragariae isolate geïdentifiseer is met relatiewe voorkomste van 69%, 25%, 6% respektiewelik. Alle Rhizoctonia isolate was patogenies op aarbeie, maar R. so/ani (AG 6) was die mees virulente en het ernstige verdwerging van plante veroorsaak. Hierdie is die eerste bevestiging van spesies en identifisering van AG tipes van Rhizoctonia taksa wat wortelvrot van aarbeie in Suid Afrika veroorsaak. In Hoofstuk 4 is 'n beraming van die voorkoms en hoeveelheid swartwortelvrot patogene geassosieer met grond voor, en na beroking met metielbromied, gemaak. Isolasies is ook vanaf kwekeryplante gemaak om te bepaal of enige swartwortelvrot patogene voor oorplanting in die plante teenwoordig was. Die resultate het getoon dat grond na beroking vry was van alle patogeniese swamme geassosieër met die siekte. Die hoof patogene betrokke in die swartwortelvrot kompleks, nl. Rhizoctonia fragariae, R. so/ani en Pythium spp. was egter in die kwekery plante teenwoordig. Die feit dat plante reeds met hierdie patogene geïnfekteer is, maak die vooruitsigte vir die beheer van hierdie siekte moeilik. Verdere studies word dringend benodig vir die ontwikkeling van produksiepraktyke wat by siektebestuursprogramme ingesluit kan word. In vitro studies om die ECso waardes van die isolate van Pythium irregulare, Rhizoctonia fragariae AG-A, AG-G en AG-I en R. so/ani AG 6 vir die fungisiedes benomyl, fludioxonil en tolclofos-metiel te bepaal, is uitgevoer. Hierdie fungisiedes is ook in veldproewe getoets. In Hoofstuk 5 is getoon dat aanwending van fungisiedes die opbrengs verbeter het en nie die oorlewing van aarbeiplante beïnvloed het nie. Fludioxonil het potensiaal vir korttermyn gebruik getoon. Die aanwending van fungisiedes wat spesifieke swamgenera teiken, was nie voldoende om die siekte te beheer nie. Seisoenale fluktuasies van Pythium en Rhizoctonia spp. het duidelik geword met die relatief hoë voorkoms van Pythium vroeg in die seisoen, maar lae voorkoms laat in die seisoen, terwyl die voorkoms van Rhizoctonia laag was aan die begin van die seisoen, maar hoog later in die seisoen. In die korttermyn is daar potensiaal vir fungisiedtoedienings as deel van 'n geïntegreerde siektebestuurstrategie, maar die ekonomiese haalbaarheid van hierdie praktyk moet bepaal word. In hierdie studie is die hoof patogene wat swartwortelvrot van aarbeie in die Wes-Kaap Provinsie van Suid-Afrika veroorsaak geïdentifiseer, en belangrike inligting rakende die epidemiologie van die siekte is aangeteken. Hierdie resultate kan in 'n geïntegreerde bestuurstrategie geïnkorporeer word om verliese van aarbeiproduksie, toeskryfbaar aan swartwortelvrot te, verminder.

Para além de um fenômeno biológico, as enfermidades são fenômenos históricos, pois a forma que a sociedade a prova é demonstrada por meio como pensam e agem em preveni-las, transmiti-las, estudá-las, compreendê-las e curá-las, e que estão calcadas pelas práticas e discursos da medicina, pelas políticas públicas desenvolvidas pelo Estado em saúde e pelos aspectos socioculturais e econômicos presentes em diferentes comunidades. A historiografia elaborou diversos estudos sobre a epidemia de AIDS (Síndrome da ImunoDeficiência Adquirida) que procuravam compreendê-la perante sua repercussão na sociedade, as comparações com outras experiências epidêmicas vividas pelas diferentes coletividades, as particularidades geográficas de infecção, a mortalidade pela enfermidade, as respostas, os preconceitos e as metáforas construídas em torno da doença por diferentes grupos sociais. Este texto apresenta o projeto de mestrado sobre como se deu a epidemia na cidade de Itapetininga (1985-1999). O presente estudo de dimensão histórica busca compreender, pelos fios dos documentos, como foram incorporados discursos e práticas sobre a AIDS no universo de uma cidade do interior paulista. Por meio da leitura da produção jornalística local e do levantamento dos projetos e requerimentos propostos na Câmara Municipal de Itapetininga, farar-se-á uma reconstrução das representações históricas sobre a doença / Beyond a biologic phenomenon, illnesses are historical fact, because of the society rehearses experience is demonstrated by show it thinks and acts to prevent, to transmit, to study, to understand, to represent and to heal. All those elements are guided by the practices and discourses of medicine, of public health policy developed by Estate and by sociocultural and economical aspects presents in many different communities. The historiography elaborated several studies about AIDS epidemic aiming at understanding it before it repercussion in society, as comparison with other epidemics by many different collectivities, the geographic infection particularities, the mortality by the illness, the answers, the preconceptions and metaphors built around of the disease by many different social groups. This work presents a master\'s degree project about how was the AIDS epidemic in Itapetininga city during the early period (1989-1996). By means of documents, the present study of historical dimension search to understand, how speeches and practices about AIDS were incorporated in the universe of a city from São Paulo State countryside. Through the reading of the local journalistic production and the survey of the projects and requirements proposed in the Municipality of Itapetininga, a reconstruction of the historical representations about the disease will be made

A presente pesquisa investiga as epidemias de febre amarela - em 1897 e 1900 - e de gripe espanhola - em 1918 - ocorridas em Sorocaba e a atuação do médico Álvaro César da Cunha Soares no seu combate, a fim de revelar as condições sanitárias de uma cidade que passava por grandes transformações, como o crescimento urbano e a industrialização, em um contexto de consolidação da medicina oficial e de acirrados debates em torno das questões relacionadas à saúde pública. Para tanto, traça-se um panorama das condições sanitárias e de saúde pública de Sorocaba entre o final do século XIX e o início do século XX, apontando o agravamento dos problemas sociais e o aumento do número de casos de determinadas enfermidades. Desse modo, pretende-se demonstrar como a condição de vida da população pobre sorocabana foi se deteriorando cada vez mais enquanto a cidade apresentava um relativo crescimento urbano e industrial. As epidemias de febre amarela são reconstituídas, abordando-se questões políticas, sociais e científicas que se desenrolaram no decorrer dos surtos epidêmicos, em um contexto de disputa entre o poder estadual, representado pelo Serviço Sanitário do Estado de São Paulo, e os poderes locais, representados por médicos e autoridades públicas municipais, na condução das medidas de combate às epidemias. A epidemia de gripe espanhola na cidade representou um desafio às autoridades públicas locais e uma ameaça à estabilidade econômica local - em um momento em que o crescimento industrial da cidade era colocado em evidência. Desse modo, estudando as epidemias que assolaram Sorocaba na virada do século XIX para o XX e acompanhando a atuação de Álvaro Soares nesse contexto, pretende-se compreender melhor a relação entre a consolidação da medicina oficial no Estado de São Paulo e suas implicações nas práticas em saúde pública / This research investigates epidemics of yellow fever - in 1897 and 1900 - and the Spanish flu - in 1918 - occurred in Sorocaba and the performance of the medical Álvaro César Soares da Cunha in combating them, in order to reveal the sanitary conditions of a city passing through major transformations, such as urban growth and industrialization, in a context of consolidation of official medicine and heated debates on issues related to public health. To this end, draws up an overview of public health and sanitary conditions of Sorocaba in the late nineteenth and the early twentieth century, pointing to the worsening of social problems and the increasing number of cases of certain diseases. Thus, it is intended to demonstrate how the living conditions of the poor in Sorocaba was deteriorating more and more as the city had a relative urban and industrial growth. The yellow fever epidemics are reconstituted, addressing political, social and scientific issues that unfolded over the outbreaks, in a dispute context between state power, represented by the State Sanitation Service of São Paulo, and local authorities, represented by physicians and municipal authorities, in the conduct of measures to combat epidemics. The Spanish flu epidemic in the city was a challenge to local public authorities and a threat to local economic stability - at a time when the industrial growth of the city was placed in evidence. Thus, studying the epidemics that ravaged Sorocaba in the late nineteenth century to the twentieth and monitoring the performance of Alvaro Soares in this context, it is intended to better understand the relationship between the consolidation of official medicine in the State of São Paulo and its implications for practice in public health

Cette thèse porte sur la modélisation des comportements individuels de vaccination. Lorsque la vaccination est libre, les individus peuvent décider ou non de se vacciner, et ces décisions influencent la propagation de la maladie. Nous proposons une approche de modélisation flexible qui permet de prendre en compte ces décisions individuelles dans les modèles de simulation épidémiologiques.Dans le Chapitre 1, nous étudions la décision de vaccination face à une maladie inspirée de la rougeole. Nous montrons comment inclure les décisions de vaccination dans un modèle épidémiologique en les calculant comme un point fixe fonctionnel. Nous obtenons des résultats pour un modèle avec taux de mort et de naissance, et perte d'immunité vaccinale. Nos résultats sur longue période de temps mettent en évidence des pics épidémiques récurrents. À titre de comparaison, nous produisons également des résultats pour des individus ayant un comportement adaptatif.Les objectifs du Chapitre~2 sont (i) de montrer que la boucle entre prévalence et comportements individuels ne peut pas être négligée dans les évaluations de politiques de santé publique, et (ii) de présenter un outil pour les inclure dans ces évaluations. Nous développons l'exemple de la vaccination obligatoire contre la rougeole. Notre modèle épidémiologique est le modèle SIR habituellement utilisé pour représenter la rougeole. Nos résultats suggèrent que l'anticipation de la vaccination obligatoire peut conduire à une augmentation transitoire de la prévalence avant l'éradication à long terme de la maladie. Ceci conduirait à d'importants transferts d'utilité entre générations. Ironiquement, dans notre scénario, des individus anti-vaccins sont parmi ceux qui bénéficient le plus de la vaccination obligatoire.Dans le Chapitre~3, nous partons du constat que la comparaison des coûts de vaccination avec le risque d'être infecté par la rougeole peine à expliquer la couverture vaccinale relativement élevée (bien que souvent insuffisante) dans les pays développés. Nous discutons l'hypothèse selon laquelle la vaccination est un comportement coopératif. Nous mettons en œuvre des concepts d'équilibre et de punition habituellement utilisés en théorie des jeux répétés en donnant des arguments pour leur utilisation dans le contexte de la vaccination. Nos résultats indiquent que la menace d'une punition peut expliquer la vaccination lorsqu'elle serait normalement sous-optimale. / We tackle the issue of including individual vaccination decisions in epidemiological models. We draw on the example of Measles vaccination, and we focus on strategic interactions and anticipatory behavior. We contribute to a fuller account of such behaviors by developing a modeling approach intended as a tool for practitioners and theorists.In Chapter 1, we show how the interplay between individual anticipatory vaccination decisions and the otherwise biological dynamics of a disease may lead to the emergence of recurrent patterns. We consider a Measles-like outbreak, rational and far-sighted individuals, vital dynamics, and waning vaccine efficacy. This chapter illustrates the versatility of our approach. For comparison, we provide results for individuals with adaptive behavior.In Chapter 2, we investigate the effect of anticipatory behavior in a scenario where Measles vaccination becomes mandatory. When mandatory vaccination is announced in advance, we show that individuals may alter their vaccination behavior, thus causing an increase in prevalence before Measles is ultimately eradicated. These transition effects lead to non negligible welfare differences between generations. We consider an anti-vaccinationist subpopulation with a higher vaccination cost, and exhibit scenarios where anti-vaccinationists are among those who benefit the most from mandatory vaccination.In Chapter 3, we discuss whether coalitions of vaccinating individuals can account for the relatively high vaccination coverages observed in developed countries. We explain why and how retaliation concepts usually found in repeated games can be used in the context of vaccination, even though individuals vaccinate only once. This allows us to model how vaccinating individuals might retaliate against those who refuse vaccination. We show that retaliation threats can sustain vaccination where it would otherwise be suboptimal for individuals.

[Truncated abstract] In March 2005, the Indian Ocean island of Reunion, a former colony and now overseas department of France, saw the first cases of what was to become a massive epidemic of the mosquito borne viral infection Chikungunya. More than 250,000 people, one third of the Island's population, were subject to high fevers, rash, and joint and muscle pains over the next 18 months, yet the public health authorities in metropolitan France were arguably slow to take the epidemic seriously. The research presented here explores attitudes underlying the management of the epidemic by examining both metropolitan and local representations of mosquito borne disease from historical, epidemiological and media perspectives. The research seeks to answer the general question Does colonial history continue to influence the representation and management of mosquito borne disease in Reunion? Three parallel approaches are taken to answering this question, using a common framework of tropicality (a Western discourse that exalts the temperate world over its tropical counterpart, and overlaps with colonialism and orientalism). ... Several factors are likely to have contributed to the persistence of tropicality in public health practice in Reunion: Othering as a universal phenomenon; the cost of administering interventions to combat tropical diseases in the remote environments of French overseas departments and territories; the denial of a serious public health risk as a cultural trait in Reunion; and the significant role of the colonies in forming and maintaining the French national identity. It has to be acknowledged that historically, tropicalism does appear to have played one positive role in the management of mosquito borne disease:

It is evident from the past forty years of research, debate and literature that the New World was far more populated in 1492 than was previously thought. However, despite the expanding field of study most works omit the effects that epidemics had on the tribes of the Great Plains, particularly those located in present-day Canada, and the works that have been published deal mainly with demographics and fail to delve into how disease affected intertribal relations. As well, almost all studies of disease and the Great Plains tribes end by 1850 or start in 1880. Therefore, the decades from 1860 through to the 1870s are largely ignored and become even more of a mystery when considering the fact that the eventual subjugation of the Plains Natives soon came when the Numbered Treaties commenced in 1871.<p>The omission of research on epidemics from 1860 to 1880 has left historians to concentrate on other reasons for the collapse of the Plains lifestyle, primarily the disappearance of the buffalo, which was crucial to Native existence in the parkland/grassland regions. Although this was obviously a very important factor in weakening warrior societies on the Plains, it was by no means the sole factor. In fact, the smallpox epidemic of 1870-71 and its after effects played an important role in debilitating Native nations, especially great tribes like the Plains Cree in present-day Saskatchewan. Food supplies could not be maintained and starvation became prevalent throughout the Great Plains in the winter of 1870-71. Malnutrition certainly would also have led to further secondary complications such as fertility problems and pulmonary illnesses, such as pneumonia, which would have contributed to the impact of the epidemic through a continued loss of population and disruption of intertribal functioning. Through analysis of the consequences of this epidemic on the Plains Cree it becomes increasingly apparent that disease played a much greater role in leading Natives towards treaty negotiations and settlement than has been formerly thought. This is not to say that epidemics in themselves were the main reason for the collapse of the Plains Cree culture, but rather they deserve to be included along with the traditional causes such as the disappearance of the buffalo.

El Hospital de Caridad de Cartagena fue fundado en 1693. Objetivo: determinar su área de influencia, los problemas sanitarios, enfermedades y lesiones más frecuentes y otros aspectos. La fuente principal ha sido el archivo del Hospital. Entre 1900 y 1936 el Hospital experimenta un gran auge. El 58% de enfermos proceden de la Ciudad, siguiéndole la zona minera (19%). Existe una correlación negativa entre los ingresos y la estancia media. Enfermedades más frecuentes: aparato digestivo (21%), respiratorias (15%), circulatorias (10%) y genitourinarias (9%). Enfermedades infecto-contagiosas más frecuentes: tuberculosis (20%), difteria (19%), paludismo (17%), sífilis (16%), fiebres tifoideas (4%) y viruela (3%). La tasa más elevada de hospitalización por paludismo corresponde a la zona húmeda de “El Hondón”. Existe una correlación negativa entre consumo de pan y de carne por estancia y número de estancias. Entre las urgencias predominan las heridas (59%), traumatismos osteoarticulares (24,3%), quemaduras (3,3%) y cuerpos extraños (2,6%). / The “Hospital de Caridad” in Cartagena was founded in 1693. Objective: to determine its area of influence, health problems, most common diseases and injuries and other aspects. The archive of the Hospital has been the main information source. Between 1900 and 1936 the Hospital experiences a great development. 58% of patients are from the City followed by those from the mining zone (19%). A negative correlation was observed between admissions and average length of inpatient hospital stay. Most frequent diseases: digestive system (21%), respiratory system (15%), cardiovascular system (10%) and genitourinary system (9%). Most frequent infect-contagious diseases: tuberculosis (20%), diphtheria (19%), malaria (17%), syphilis (16%), typhoid fever (4%) and smallpox (3%). The main zone affected by malaria is the wetland area called “El Hondón”. A negative correlation was observed between bread and meat consumption per hospital stay and average length of stay. Most common emergencies are wounds (59%), osteoarticular traumatisms (24.3%), burns (3.3) and foreign bodies (2.6%).

It is evident from the past forty years of research, debate and literature that the New World was far more populated in 1492 than was previously thought. However, despite the expanding field of study most works omit the effects that epidemics had on the tribes of the Great Plains, particularly those located in present-day Canada, and the works that have been published deal mainly with demographics and fail to delve into how disease affected intertribal relations. As well, almost all studies of disease and the Great Plains tribes end by 1850 or start in 1880. Therefore, the decades from 1860 through to the 1870s are largely ignored and become even more of a mystery when considering the fact that the eventual subjugation of the Plains Natives soon came when the Numbered Treaties commenced in 1871.<p>The omission of research on epidemics from 1860 to 1880 has left historians to concentrate on other reasons for the collapse of the Plains lifestyle, primarily the disappearance of the buffalo, which was crucial to Native existence in the parkland/grassland regions. Although this was obviously a very important factor in weakening warrior societies on the Plains, it was by no means the sole factor. In fact, the smallpox epidemic of 1870-71 and its after effects played an important role in debilitating Native nations, especially great tribes like the Plains Cree in present-day Saskatchewan. Food supplies could not be maintained and starvation became prevalent throughout the Great Plains in the winter of 1870-71. Malnutrition certainly would also have led to further secondary complications such as fertility problems and pulmonary illnesses, such as pneumonia, which would have contributed to the impact of the epidemic through a continued loss of population and disruption of intertribal functioning. Through analysis of the consequences of this epidemic on the Plains Cree it becomes increasingly apparent that disease played a much greater role in leading Natives towards treaty negotiations and settlement than has been formerly thought. This is not to say that epidemics in themselves were the main reason for the collapse of the Plains Cree culture, but rather they deserve to be included along with the traditional causes such as the disappearance of the buffalo.

We investigate a certain epidemics model, with and without noise. Some parameter analysis is performed together with computer simulations. The model was presented in Iacus (2008).